Smelting apparatus and metallurgical processes thereof

ABSTRACT

The present document describes a smelting apparatus for smelting metallic ore. The smelting apparatus comprises a furnace having a continuous curved wall and end walls defining a longitudinal volume having a longitudinal axis in a horizontal direction. The continuous curved wall has a lowermost area. The longitudinal volume is divided in at least three longitudinal layers comprising a top layer within which gasified fuel is combusted for creating a hot gas composition at a temperature sufficient to release, from the metallic ore, at least molten metal and slag, a lowermost layer at the lowermost area for holding molten metal, and a mid-layer above the lowermost layer in which the slag accumulates. The present document also describes processes using the smelting apparatus for producing ferrous and non-ferrous minerals from a metallic ore.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of U.S. provisional patent applicationNo. 61/883,673, filed on Sep. 27, 2013, the specification of which ishereby incorporated by reference. This application is acontinuation-in-part (CIP) of U.S. patent application Ser. No.15/023,178, filed Mar. 18, 2016.

BACKGROUND (a) Field

The subject-matter disclosed generally relates to smelting apparatus andto smelting processes. More particularly, the subject-matter relates tosmelting apparatus for iron ore and processes for smelting iron ore.

(b) Related Prior Art

Smelting is a form of extractive metallurgy. Its main use is to producea metal from its ore. This includes production of silver, iron, copperand other base metals from their ores. Smelting uses heat and a chemicalreducing agent to decompose the ore, driving off other elements asgasses or slag and leaving just the metal behind. The reducing agent iscommonly a source of carbon such as coke or charcoal. The carbon and/orcarbon oxide derivative react(s) with the ore to remove oxygen from theore, leaving behind elemental metal. The carbon is thus oxidized in twostages, producing first carbon monoxide and then carbon dioxide. As mostores are impure, it is often necessary to use flux, such as limestone,to remove the accompanying rock gangue as slag.

Plants for the electrolytic reduction of aluminum are also generallyreferred to as smelters. These do not melt aluminum oxide but insteaddissolve it in aluminum fluoride. They normally use carbon electrodes,but novel smelter designs use electrodes that are not consumed in theprocess. The end product is molten aluminum.

Smelting involves more than just melting the metal out of its ore. Mostores are a chemical compound of the metal with other elements, such asoxygen (i.e., an oxide derivative), sulfur (i.e., a sulfide derivative)or carbon and oxygen together (i.e., a carbonate derivative). To producethe metal, these compounds have to undergo a chemical reaction. Smeltingtherefore consists of using suitable reducing substances that willcombine with those oxidizing elements to free the metal.

Current smelting furnace designs are more than often either tallvertical cylinders or rectangular boxes. Both result in either highconstruction costs for the tall cylindrical approach, or highoperational and maintenance costs associated with the refractorymaterial for rectangular box designs since refractory is not stable inbox type designs.

Numerous types of furnaces exist on the market. In an example, U.S. Pat.No. 6,537,342 describes an apparatus for a metal reduction and meltingprocess, in which a metal and carbon-containing burden is heated in aninduction furnace including a heating vessel in which the burden canfloat in at least one heap on a liquid metal bath in the vessel. Theapparatus is characterized in that it includes at least one inductionheater or inductor located at the bottom center line of the vessel, withthe longitudinal access oriented perpendicular to the access of thevessel. The furnace is generally electrically heated from the outsidevia induction means.

Even if U.S. Pat. No. 6,537,342 provides a cylindrical design to itsfurnace, it leads to an inefficient way of providing heat to the furnacebecause heat needs to travel towards the wall of the furnace as well asthrough the refractory material before heating the interior of thefurnace.

In another example, U.S. Pat. No. 6,146,437 describes a metal-containingcompound reduction and melting process which entails feeding a burdenmade of a mixture of the metal containing compound and a suitable bathof the metal in liquid form so that a reaction zone is formed in theburden in which the metal-containing compound is reduced and a meltingzone is formed below the reaction zone in which the reduced metal ismelted. The furnace is generally electrically heated from the outsidevia electrical means.

Even if U.S. Pat. No. 6,146,437 provides a cylindrical design to itsfurnace, it leads to an inefficient way of providing heat to the furnacesince the heat needs to travel towards the wall of the furnace as wellas through the refractory material before heating the interior of thefurnace. Use of electrical heating is both costly and inefficient.

In another example, U.S. Pat. No. 5,411,570 describes a method of makingsteel by heating in a channel type induction furnace an iron containingburden and carbon. The carbon is included in the burden and/or containedin hot metal. The temperature of the liquid product so formed ismaintained above its liquidus temperature by controlling the amount ofheat supplied to the furnace and/or the rate at which the burden isadded to the furnace.

Even if U.S. Pat. No. 5,411,570 provides a cylindrical design to itsfurnace, it leads to an inefficient way of providing heat to the furnacesince the heat needs to travel towards the wall of the furnace as wellas through the refractory material before heating the interior of thefurnace.

In another example, Canadian application CA2934973 describesmetallurgical processes and a generally square or rectanglemetallurgical furnace capable of operating with a wide range of rawmaterials and fuels. Particularly, the heat is provided to the furnaceby at least one burner in conjunction with at least one row of clackvalves. However, the generally square design of the square or rectanglemetallurgical furnace makes it difficult to scale up the processedcarried out by such furnace.

In another example, Canadian application CA2970818 describesmetallurgical processes and a metallurgical furnace that is capable ofoperating with a wide range of raw materials and fuels. Particularly,the furnace includes at least one curtain wall located in the uppervessel, which extends longitudinally down the furnace, and at least onebooster loading system in the center of the upper vessel, which alltogether control the distribution of gas in the furnace. However, thevertical design of the metallurgical furnace makes it difficult to scaleup the processed carried out by such furnace.

There is therefore a need for an improved smelting apparatus and for aprocess of operating the same.

SUMMARY

According to an aspect, there is provided a smelting apparatus forsmelting metallic ore, the smelting apparatus comprises a cylindricalfurnace having: a continuous curved wall with a longer axis along ahorizontal direction, and end walls joining the continuous curved walland thereby defining a longitudinal volume in the horizontal direction,the continuous curved wall having a lowermost area, wherein thelongitudinal volume is divided in at least three longitudinal layerscomprising a top layer within which gasified fuel is combusted forcreating a hot gas composition at a temperature sufficient to release,from the metallic ore, at least molten metal and slag, a lowermost layerat the lowermost area for holding molten metal, and a mid-layer abovethe lowermost layer in which the slag accumulates.

According to an aspect, the smelting apparatus further comprises a rawmaterial inlet within the continuous curved wall in fluid communicationwith the top layer for supplying the metallic ore to the furnace, and acombustion air inlet within the continuous curved wall in fluidcommunication with the top layer for providing air for inducingcombustion in the furnace.

According to an aspect, the smelting apparatus further comprises amolten metal outlet in the lowermost area of the continuous curved wallin fluid communication with the lowermost layer for allowing moltenmetal to exit the furnace continuously and selectively.

According to an aspect, byproduct gases are released from the metallicore and hot gas composition, and further wherein the continuous curvedwall comprises an uppermost area which comprises a byproduct hot gasoutlet fluidly connected to the furnace providing an exit from thefurnace for the byproduct gases.

According to an aspect, the smelting apparatus further comprises a fuelinlet within the continuous curved wall in fluid communication with thetop layer for supplying a fuel to the furnace and a hot gas inlet withinthe continuous curved wall in fluid communication with the top layer forsupplying a hot gas to the furnace for gasifying the fuel, therebyproducing the gasified fuel.

According to an aspect, the smelting apparatus further comprises a hotgas generator for providing gasified fuel and a gasified fuel inletwithin the continuous curved wall in fluid communication with the toplayer for supplying gasified fuel to the furnace.

According to an aspect, the furnace comprises an interior surface, theinterior surface being lined with a refractory material.

According to an aspect, the smelting apparatus further comprises acooling system operatively connected to the furnace for cooling anexterior surface of the furnace.

According to an aspect, there is provided a process for smeltingmetallic ore, comprising: providing magnetite and/or iron oxide producedfrom the metallic ore by hydrometallurgy; producing a hot reducingatmosphere by gasification; and contacting the magnetite and/or ironoxide with the hot reducing atmosphere to produce a molten metal,wherein the contacting is performed in a smelting apparatus comprising acylindrical furnace having a continuous curved wall with a longer axisalong a horizontal direction, and end walls joining the continuouscurved wall and thereby defining a longitudinal volume in the horizontaldirection.

According to an embodiment, the magnetite is produced by magneticseparation, density, or flotation during hydrometallurgy.

According to an embodiment, Fe₂O₃ is produced by solvent extraction andacid regeneration during hydrometallurgy.

According to an embodiment, the iron oxide and/or the hot reducingatmosphere comprises a source of carbon other than coke or coal.

According to an embodiment, the hot reducing atmosphere is produced bygasification of carbonaceous material.

According to an embodiment, the contacting of the magnetite and/or ironoxide with the hot reducing atmosphere further produces a byproduct gasused as a source of energy for the hydrometallurgy or for devolatizationof biomass.

According to an embodiment, the source of energy is used for acidregeneration for the hydrometallurgy.

According to an embodiment, the molten metal is pig iron.

According to an embodiment, the molten metal is a ferro-manganese alloy,a ferro-nickel alloy, and/or a ferro-vanadium alloy.

According to an embodiment, the process is for smelting metallic orecontaining trace elements, wherein the contacting of the magnetiteand/or iron oxide with the hot reducing atmosphere further produces aslag containing the trace elements.

Features and advantages of the subject-matter hereof will become moreapparent in light of the following detailed description of selectedembodiments, as illustrated in the accompanying figures. As will berealized, the subject-matter disclosed and claimed is capable ofmodifications in various respects, all without departing from the scopeof the claims. Accordingly, the drawings and the description are to beregarded as illustrative in nature, and not as restrictive and the fullscope of the subject-matter is set forth in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present disclosure will becomeapparent from the following detailed description, taken in combinationwith the appended drawings, in which:

FIG. 1 is a front elevation cross-sectional view of a smelting apparatusin accordance with an embodiment; and

FIG. 2 is a front elevation cross-sectional view of a smelting apparatusin accordance with another embodiment.

FIGS. 3 and 4 are a box diagrams representing a process combining apyrometallurgical process and a hydrometallurgical process.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION

In embodiments there are disclosed smelting apparatus and processes ofoperating the same.

Smelting Apparatus

Referring now to FIG. 1 and according to an embodiment, there is shown asmelting apparatus 10. The smelting apparatus 10 is for smeltingmetallic ores. The smelting apparatus 10 includes a horizontallyoriented cylindrical furnace 12 which has an interior surface 14 and anexterior surface 16. The smelting apparatus 10 further includes a fuelinlet 18 which is operatively connected to the furnace 12 for providinga fuel in the furnace 12. According to an embodiment, the fuel includes,without limitation, coal, petcoke, coke, biomass carbon (i.e., eitherpowder or briquetted), and the like.

The smelting apparatus 10 further includes a raw material inlet 20 whichis operatively connected to the furnace 12 for providing a raw materialin the furnace 12. According to an embodiment, the raw materialincludes, without limitation, any fine ore which meets the overalleconomic requirements and additional flux materials as required for thechemical balance of the process (process reactions described below).More specifically, the raw material may be fine iron ore which meets theoverall economic requirements and additional flux materials as requiredfor the chemical balance of the process which is involved within thefurnace 12.

The smelting apparatus 10 further includes a hot gas inlet 22 which isoperatively connected to the furnace 12 for providing a hot gas in thefurnace 12. It is to be mentioned that while any hydrocarbon gas can beused, natural gas is an economically viable choice. The smeltingapparatus 10 further includes a combustion air inlet 24 which isoperatively connected to the furnace 12 for providing air inducingcombustion in the furnace 12. It is to be mentioned that, while thefurnace 12 is in operation, combustion from combustion air entering thefurnace 12 via combustion air inlet 24, is not complete to provideoxidation in the second step of the chemical reaction.

The purpose of the oxidation is to generated a self-reducing atmosphereby producing a mix of primarily CO and some CO₂ which will react withthe ore thereby removing oxygen from the ore, reducing the ore to themetallic form and shifting the gas composition to primarily CO₂. Theself-reducing atmosphere may be generated with coal, coke, natural gas,biomass, hydrogen and electricity.

It is to be mentioned that the amount of heat needed for the smeltingprocess involved within the furnace 12 is internally provided within thefurnace 12.

The smelting apparatus 10 further includes a metal outlet 26 which isoperatively connected to the furnace 12 for the metal to exit (i.e.,continuously exit) the furnace 12. The smelting apparatus 10 may furtherinclude a slag outlet 30 which is operatively connected to the furnace12 for slag to exit (i.e., periodically exit) the furnace 12. The slagis made from the non-metallic elements in the ore and the fluxes addedwith the raw material charge to assure that the slag is molten at thefurnace operating temperature.

Additionally, according to an embodiment, the smelting apparatus 10further includes a byproduct hot gas outlet 32 operatively connected tothe furnace 12 for the byproduct hot gas to exit the furnace 12. Afterthe various chemical reactions are completed within the furnace 12 andthe ore is reduced to metal, the byproduct hot gas is a combination ofCO, CO₂ and N₂ (in the case when natural gas is the fuel).

According to another embodiment, the interior surface 14 is refractorylined. The refractory material used for the interior surface 14 mayinclude, without limitation, various carbon-based materials andAl₂O₃-based materials.

According to another embodiment, the refractory materials used will varydepending on their location within the furnace 12 as a function ofprocess temperature and location. For example, various carbon-basedmaterials may be used in the lower portion of the furnace 12, whileAl₂O₃-based materials may be used in the upper portion of the furnace12. Both preformed fired bricks and castable materials may be used as afunction of location and economics.

According to another embodiment, the smelting apparatus 10 may furtherinclude a cooling system 28 which may be operatively connected to thefurnace 12 for cooling the exterior surface 16 of the furnace 12. Thefurnace 12 may be cooled with water based on economics. Water may berecirculated through a common heat exchanger and reused as the coolingagent or fluid.

According to an embodiment, there is provided a smelting apparatus 10for smelting metallic ore. The smelting apparatus 10 comprises a furnace12 having a continuous curved wall 15 and end walls (not shown) defininga longitudinal volume having a longitudinal axis in a horizontaldirection. The continuous curved wall 15 has a lowermost area 17. Thelongitudinal volume is divided in at least three longitudinal layerscomprising a top layer (A) within which gasified fuel is combusted forcreating a hot gas composition at a temperature sufficient to release,from the metallic ore, at least molten metal and slag, a lowermost layer(C) at the lowermost area for holding molten metal, and a mid-layer (B)above the lowermost layer in which the slag accumulates.

In operation, within the furnace 12, the fuel is gasified to create ahot fuel gas that is combusted by the combustion air creating a hot gascomposition and a temperature to smelt the metallic ores. For iron ores,these chemical reactions occurring within the furnace 12 result in thefollowing chemical formulas:

C+O₂=CO+CO₂ (Fuel Gasification)

CO+FeO=CO₂+Fe

C+CO₂=2 CO

It is to be noted that not only FeO, but all forms of iron oxides (e.g.Fe₃O₄ and Fe₂O₃ (hematite)) may be reduced to pig iron in metallic formby the furnace 12. It is to be further noted that similar reactions mayoccur within the furnace 12 for other metallic elements that are in theore (other than iron). For example, in the case of manganese (IV) Oxide(MnO₂), reaction occurs according to the following chemical equation:

MnO₂+C=MnO+CO (Fuel Gasification)

MnO₂+CO=MnO+CO₂

MnO+C=Mn+CO

These reactions generally occur below 900° C., and the final reductionof MnO only takes place with solid carbon. The reaction is highlyendothermic. In the case of Nickel (II) Oxide (NiO), the reaction occursaccording to the following chemical equation:

NiO+C=Ni+CO (Fuel Gasification)

Advantageously, the smelting apparatus 10 as described above utilizes ahorizontally oriented cylindrical furnace 12 defining a horizontal axiswhich combines the low height approach of the box concept with theinherent refractory stability of the cylindrical approach.

According to another embodiment, the smelting apparatus 10 may be usedto process mine and steel mill waste products.

According to a further embodiment, the smelting apparatus 10 may be usedwith a broad range of carbon sources. As mentioned above, carbon sourcesmay include, without limitation, coal, charcoal, coke, petcoke, andbiomass (i.e., sawdust), and the like.

According to yet another embodiment, the smelting apparatus 10 may beused for other metals, such as, without limitation, silver, copper andother base metals from their ores.

The smelting apparatus 10 has a horizontally oriented cylindricalfurnace 12. The system capacity operating the smelting apparatus 10 maybe expanded readily by making the furnace 12 longer. Both diameter andlength may be variable. As such, doubling the length would double theproduction rate and doubling the diameter would quadruple the productionrate.

According to an embodiment, the interior diameter of the furnace 12 mayvary from about 3 meters to about 6 meters and the length of the furnace12 may vary from about 6 meters to about 30 meters, as a function of adesired production capacity. For example, the capacity of the smeltingapparatus may be about 1,500 tons or more of molten metal per day.

The smelting apparatus 10 may further include, without limitation, hotair delivery options, tuyeres (i.e., ceramic tuyeres, cast metal watercooled tuyeres and/or uncooled ceramic tuyeres.), continuous casting,raw material charging options and the like (not shown).

According to another embodiment, the furnace 12 may be filled utilizinga static multi-point raw material charging system to provide the rawmaterial to the raw material inlet 20 and into the furnace 12.

According to an embodiment, the smelting apparatus 10 may be provided invarious size or may be designed to be scalable in order to acceptvarious loads of starting material. For example, the furnace 12 of thesmelting apparatus 10 may be scalable by adjusting the length thereof inorder to suit specific production requirements. For example, the furnace12 may be configured for smelting iron ore which market capacities areat least of 500,000 tons per year, ferro alloys which market capacitiesare typically 50,000 tons per year, or ferrovanadium which marketcapacities are typically 10,000 tons per year.

Advantageously, the furnace 12 has a low height design which eliminatesthe requirement for a highly reactive fuel, such as, without limitation,metallurgical coke. The low height design of furnace 12 also eliminatesthe requirement for important structural support under the furnace 12.

The furnace 12 may have a refractory lining extending from the interiorsurface 14 which is inherently stable under operating conditions. Thisconfiguration allows long furnace life and stable operating conditions.

Operation of the Smelting Apparatus

In embodiments there are disclosed operation of the smelting apparatusin various processes for smelting ore.

Still referring to FIG. 1, during operation of the smelting apparatus10, the fuel is charged to the furnace 12 via the fuel inlet 18. Thefuel may be lump carbonaceous fuel or any other suitable fuel. The fuelmay be continuously charged to the furnace 12. Alternatively, the fuelmay also be fed in batch to the furnace 12. The fuel inlet 18 may belocated on the side of the furnace 12, or at any location at theperiphery of the furnace 12 such as to fluidly connect the fuel inlet 18and the furnace 12.

The raw material is charged to the furnace 12 via the raw material inlet20. The raw material may be continuously charged to the furnace 12 orcharged in a batch operation to the furnace 12. The raw material may befed on the top of the furnace 12 via the raw material inlet 20.

The hot gas may be injected to the furnace 12 via the hot gas inlet 22.The hot gas may be, without limitation, hot blast air. The hot gas maybe injected via the hot gas inlet 22 below the carboneous fuel inlet 18,or at any location at the periphery of the furnace 12.

Combustion air is injected to the furnace 12 via the combustion airinlet 24. The combustion air may be post combustion air and may beinjected to the furnace 12, without limitation, at the base of the rawmaterial inlet 20.

The carbonaceous fuel is then gasified in an oxygen lean environment tocreate a hot fuel gas that is combusted by the post combustion aircreating the necessary hot gas composition and temperature to smelt theore feed.

The smelted ore descends to the base of the furnace 12 where the metalwill separate from the non-metallic components (i.e., slag). The metalis cast (or continuously cast) from the metal outlet(s) 26 of thefurnace 12. It is to be noted that the metal outlet 26 may be located atthe bottom portion of the furnace 12. Only a few inches of molten metalneed to be left in the bottom portion of the furnace 12 to prevent gascommunication from the bottom portion such as to prevent oxygen to enterthe furnace 12.

The slag may be cast (or periodically cast) from the furnace 12 via theslag outlet(s) 30 by opening a recess on the side of the furnace 12 toallow the slag to exit the furnace 12 or by periodically drilling a holein the wall of the furnace 12 at the height of the slag (at themid-layer) to enable the slag to exit the furnace 12. The furnacebyproduct gas (N₂, CO and CO₂) leaves the furnace 12 via the byproducthot gas outlet(s) 32 to be transferred to environmental treatment andsubsequent energy recovery. It is to be mentioned that the byproduct hotgas may be, without limitation, reused within the hot gas (or hotblast), sold as a fuel, used/sold to heat a boiler to produceelectricity, and the like (depending on the geographical location).

In an embodiment, the smelting apparatus 10 is operated continuouslyunder a positive pressure and a reducing atmosphere.

In an embodiment, there is no combustion inside the furnace 12 of thesmelting apparatus 10 so that under normal operation the gases in thefurnace 12 are reducing and any leakage will be from inside the furnaceto the atmosphere.

Referring now to FIG. 2 and according to another embodiment, the furnace12 may include gas burner(s) or hot gas generator(s) which is connectedto a gasified fuel inlet 34 that will replace the use of thecarbonaceous fuel inlet 18 and the hot gas inlet 22 (i.e., the use ofsolid fuel and hot air blast). The hot products of combustion mayprovide the necessary thermal energy to assure molten products, metaland slag, at the outlets 26, 30 of the furnace 12. The primary chargematerial, self-reducing briquettes may be adjusted in their overallchemistry to offset any changes in the overall furnace chemical balance.

According to another embodiment, it is to be noted that all inlets andoutlets 18, 20, 22, 24, 26, 30, 32 of the furnace 12 may include aplurality of inlets/outlets as a function of the overall length and/ordiameter of the furnace 12.

One of the advantages of the smelting apparatus 10 as described above isthe horizontal orientation of the cylindrical design, which utilizes thepressure containment advantages of the cylindrical approach (verticallyoriented cylindrical approach) without the cost disadvantages of highconstruction, while avoiding the refractory instability associated withthe rectangular approach (horizontally oriented rectangular approach).According to the configuration of the smelting apparatus 10 as describedabove, no induction/electrical heating (i.e., which is costly and lessefficient) is employed for providing heat to the interior of the furnace12, all the heat required for the process is generated from the carbon(i.e., lump carbonaceous fuel) charged to the furnace 12. Furthermore,the furnace 12 is fixed; i.e., it does not rotate.

According to the configuration of the smelting apparatus 10, anotheradvantage is that there is no accumulation of the molten metal in thefurnace 12 and the process is not dependent on this accumulation. Allmetal produced is continuously cast from the furnace 12.

Ore Smelting Processes Using the Smelting Apparatus

In embodiments there are disclosed uses of the smelting apparatus 10 invarious processes for smelting iron ore and/or various ferro alloys.There are also disclosed embodiments for recovery of non-ferrous metaland critical or trace elements, such as valuable or precious metals,from primary and secondary slags formed during the processes forsmelting iron ore and various ferro alloys.

Referring now to FIG. 3 and according to an embodiment, there is shownthe smelting apparatus 10 which is used in a pyrometallurgical process30 (e.g. ore smelting) in combination with a hydrometallurgical process40 (e.g. ore leaching) for producing high-value pig iron 60 and/orextracting valuable or precious metals in a cost-effective manner. Asshown in FIG. 3, the combined pyrometallurgical/hydrometallurgicalprocess 50 uses as starting material magnetite 52 isolated by a magneticseparation step 54 from the ore and Iron (II) Oxide (FeO) 56 (or anyother form of iron oxide, e.g. Fe₃O₄ and Fe₂O₃ (hematite)) obtained froman acid regeneration step 42 of the hydrometallurgical process 40.Alternatively, the magnetite 52 may be isolated by any other means knownin the art, such as by flotation, density, and the like. Stillalternatively, any other suitable starting material, such as wastematerials containing iron and/or valuable or precious metal(s), may beused and may be produced and provided to the smelting apparatus 10 byany means known in the art.

In an embodiment, the starting material of feed for the smeltingapparatus 10 used in the combined process 50 is has over about 50% Fecontent and may be in any form of iron oxide (e.g. FeO, Fe₃O₄, Fe₂O₃(Fe₂O₃)).

For powering the smelting apparatus 10, coal, biomass, plastic wastes,and/or any other source of low-cost material 56 is used as energy sourceto operate the combined process 50. Indeed, the smelting apparatus 10may be operate with a wide range of carbonaceous material as both theenergy source and chemical reductant, such as bearing wastes and wasteplastics materials. The treatment of such waste materials may generallybe energy intensive to treat, and this energy requirement may beeffectively satisfied by the off gas 58, which is a byproduct gas.

As part of the cost-effective manner of operating the smelting apparatus10 in the combined process 50, the off gas 58 produced by the smeltingapparatus 10 during the pyrometallurgical process 30 is collected andused as an energy source to operate the acid regeneration step 42 of thehydrometallurgical process 40. This provides for a low-cost acidregeneration alternative to the hydrometallurgical acidic solutions. Forexample, for every ton of pig iron produced an equivalent excess gas of10 GJ may be produced, which may be used for the hydrometallurgicalprocess. In the case of ferro alloys, between about 10 and about 15 GJmay be produced. Alternatively, the energy source derived from the offgas 58 may be used for any other step(s) of the hydrometallurgicalprocess, such as a calcining step, a heating step, an evaporation step,and the like.

Furthermore, the combined process 50 provides a self-contained solutionfor the non-ferrous metal industries that converts iron bearing wastesinto a high value saleable product and, thus, eliminates the need foriron bearing wastes to be landfilled. According to the presentinvention, all forms of iron bearing wastes recovered may be convertedto pig iron from any form. Indeed, the extraction of non-ferrous metalsin the mining industry often generates significant quantities of ironwaste material that currently is returned to the environment either as asolid waste landfilled back to the area of the excavation. Also, therecovery of iron in chloride solutions through acid regeneration isgenerally very costly and energy intensive and often there is not userfor the hematite units produced. Generally, the cost of addressing theiron material to comply with environmental regulations is sufficientlyhigh to make the commercialization of non-ferrous mines or chemicalprocessing centers high and uneconomical. There is a market for ironchlorides for the water treatment industry but this is easy to saturateand very region-oriented. By converting the iron to pig iron tailingsare reduced and the energy/gas by product can be used for thehydrometallurgical process and to supply gas for the acid regenerationunit unlocking the value of the non-ferrous mine. The pig iron has ahigh value and helps address the energy challenges of these industrieswhile reducing environmental impacts by converting more of the wastestreams into usable products.

As for the recovery of iron in chloride solutions through acidregeneration is generally very costly and energy intensive and oftenthere is not user for the hematite units produced. Generally, the costof addressing the iron material to comply with environmental regulationsis sufficiently high to make the commercialization of non-ferrous minesor chemical processing centers high and uneconomical. There is a marketfor iron chlorides for the water treatment industry but this is easy tosaturate and very region oriented. By converting the iron to pig irontailings are reduced and the energy/gas by product can be used for thehydrometallurgical process and to supply gas for the acid regenerationunit unlocking the value of the non ferrous mine. The pig iron has ahigh value and helps address the energy challenges of these industrieswhile reducing environmental impacts by converting more of the wastestreams into usable products.

In an embodiment, the product streams resulting from the smeltingapparatus 10 includes (i) metallic pig iron, metallic ferro alloys (FeMnand/or FeNi), and materials of high-value in steelmaking; and (ii) atleast one smelting process slag that is chemically controlled to beproduced as a liquid wherein the proportions of the desired traceelements or valuable or precious metal(s) are increased by a factor ofbetween about 4 and about 5 times.

In an embodiment, the combined process 50 and the smelting apparatus 10is used to process ore containing non-ferrous metal(s), such asmanganese (Mn), nickel (Ni), vanadium (V), some rare earth metal(s), andalloys thereof. Those non-ferrous metals and alloys thereof are notreduced during smelting to remain as metallic oxides and are principallyfound in and recovered from a primary slag (which also contains MgO, CaOand titanium dioxide (TiO₂), for example) formed during smelting. Somecritical or strategic elements, such as vanadium and scandium (Sc), mayalso be found in the primary slag, but may also be found in a secondaryslag (see hereinbelow). These critical or strategic elements arerecovered from the primary and secondary slags by hydrometallurgyprocesses. The non-ferrous elements are extracted from the primary slagby leaching or selective leaching cycles and by liquid-liquid separation(e.g. using a resin or by solvent extraction).

In an embodiment, critical or trace elements, such as vanadium,scandium, and some rare earth metal(s), are concentrated up to 20 timesin a secondary slag. In the case of vanadium, for example, it isgenerally found at about 50% in the primary slag and at about 50% in pigiron. Scandium and other precious metals are found in the primary slagand pig iron in amount similar to the amount of vanadium. Variouscritical elements are also generally found in the primary slag and inpig iron to be collected in the secondary slag or in percentages. Bychanging the slag pH and creating a secondary slag, vanadium, scandiumand some rare earths metal(s) are concentrated with better ratios ofiron and salt metals, such as Mg and Ca, in the secondary slag, therebyimproving the operating costs of recovering vanadium, scandium and somerare earths metal(s). Metalized critical elements in the molten pig ironmay be recovered in the secondary slag. This helps to reduce the volumeby 1/10^(th) to 1/60^(th) of the initial starting volume. In addition,the iron making process reduces tailings and provides energy for thehydrometallurgical process and improves IRR by converting iron richtailings into salable products.

In an embodiment, a secondary gangue stream is formed during operationof the smelting apparatus 10. The secondary gangue stream is cooled to asolid, and crushed. The crushed gangue stream is treated withconcentrated nitric acid, which primarily and selectively dissolve theCaO and MgO portions of the gangue, leaving SiO₂ and Al₂O₃ as theprincipal remaining compounds. Then, leaching with HCl or Sulphuric acidachieves targeting the metals focused of recovery and purification byliquid-liquid separation (e.g. using a resin or by solvent extraction).The valuable or precious metal(s) are concentrated in the remainingsolids by a factor of two as compared to the ore. The resulting liquidstream of metallic nitrates may be use as a feedstock for furtherprocessing as fertilizer. The remaining solid stream, which may containSiO₂, Al₂O₃, and other valuable or precious metals, is then dissolved inhydrochloric acid. The resulting liquid being treated by a series oforganic liquids to preferentially remove individual elements based onconcentration and monetary value. In order to recycle the acid used forleaching and reduce costs, the acid used is regenerated using the offgas of the smelting apparatus 10 as the energy source.

The treatment of the secondary gangue stream requires energy forevaporation or heating or acid regeneration, for example. HCl is theonly one that allows for acid regeneration. More acid regeneration isenabled by providing energy to do this and creating complete recovery ofHCl and iron units. Acid regeneration also works with MgCl₂. Forexample, the highest throughput for iron rich solution is when the ironis in Fe³⁺form FeCl₃ as Fe³⁺produces 185 to 210 gpl, while Fe²⁺produces140 gpl maximum.

In an embodiment, the smelting apparatus 10 produces (i) pig with aniron content of 94% or higher; (ii) manganese in the form of ferromanganese in varying ratios of manganese to iron with a total metalliccontent of 94% or higher; (iii) nickel in the form of ferro nickel invarying ratios of nickel to iron with a total metallic content of 94% orhigher; and (iv) vanadium in the form of ferro vanadium in varyingratios depending on the ratio of V₂O₅ with a total metallic content of94% (iron is added).

In an embodiment, the combined process 50 and the smelting apparatus 10is used with self-reducing pellets or briquettes known in the art as amethod of accelerating the smelting reactions of iron ore. In this case,the scalability of the smelting apparatus 10 and the use ofself-reducing briquettes allows the economic smelting of ferruginousores and wastes contaminated by other metals. Particularly, thefunctionality of the self-reduction pellets or briquettes approach relyon intimately mixing and agglomerating all the finely ground materialsrequired for smelting, such as ore, appropriate wastes, fuel, andfluxes, with a functional binder. The agglomeration of these materialsproduces a self-contained system that, when exposed to the requiredthermal input and atmosphere of smelting, reduces to a metal and moltenslag(s).

In an embodiment, the self-reducing briquette may also use biomass thatis devolatized.

In an embodiment, the smelting apparatus 10 advantageously replace aconventional blast furnace, eliminate the need for coking coal, and uselow to medium volatile thermal coal during operation of the combinedprocess 50.

In an embodiment, the smelting apparatus 10 is more efficient than aconventional blast furnace (which are generally bigger in size), suchthat operating the smelting apparatus 10 during about 20 minutesprovides the same smelting results as operating a conventional blastfurnace for about 8 hours.

In an embodiment, the smelting apparatus 10 may advantageously replacecostly electric furnaces that are normally operated as twin shells andgenerally cost more than 4 times the capex.

Advantageously, due to its horizontal and cylindrical design, thesmelting apparatus 10 of the present invention may be used to produceferro alloys, such as ferro-manganese, ferro-nickel, and ferro-vanadium,at a substantially lower cost as compared to using a blast furnace.

Another advantage of the smelting apparatus of the present invention isthat it may smelt ore that would otherwise require to be sintered orpelletized to be amenable to smelting. This in turn allows for areduction of between about 20% to about 30% of CO₂ that is usuallyrequired by the smelting process and, thus, reduces operation cost. Byeliminating the agglomeration process of pellets 20% less CO₂ isemitted. By eliminating the sintering process 30% less CO₂ is emittedcompared to the conventional iron making with a blast furnace. Inaddition, due to faster reaction time with the combined self-reducingbriquette and hot blast for melting, the smelting apparatus 10, may usecoke, metallurgical coal, and/or less desirable coals (e.g. low volatileand medium volatile coals), for the self-reducing briquettes, and anytype of thermal coal for the energy portion. Alternatively, natural gas,hydrogen and electricity can all be used as energy sources with thesmelting apparatus 10.

Advantageously, the smelting apparatus 10 of the present invention maybe operated without requiring coke and/or coke as it generally the casefor smelting.

While preferred embodiments have been described above and illustrated inthe accompanying drawings, it will be evident to those skilled in theart that modifications may be made without departing from thisdisclosure. Such modifications are considered as possible variantscomprised in the scope of the disclosure.

1. A smelting apparatus for smelting metallic ore, the smeltingapparatus comprising a cylindrical furnace having: a continuous curvedwall with a longer axis along a horizontal direction, and end wallsjoining the continuous curved wall and thereby defining a longitudinalvolume in the horizontal direction, the continuous curved wall having alowermost area, wherein the longitudinal volume is divided in at leastthree longitudinal layers comprising a top layer within which gasifiedfuel is combusted for creating a hot gas composition at a temperaturesufficient to release, from the metallic ore, at least molten metal andslag, a lowermost layer at the lowermost area for holding molten metal,and a mid-layer above the lowermost layer in which the slag accumulates.2. The smelting apparatus of claim 1, further comprising a raw materialinlet within the continuous curved wall in fluid communication with thetop layer for supplying the metallic ore to the furnace, and acombustion air inlet within the continuous curved wall in fluidcommunication with the top layer for providing air for inducingcombustion in the furnace.
 3. The smelting apparatus of claim 2, furthercomprising a molten metal outlet in the lowermost area of the continuouscurved wall in fluid communication with the lowermost layer for allowingmolten metal to exit the furnace continuously and selectively.
 4. Thesmelting apparatus of claim 3, wherein byproduct gases are released fromthe metallic ore and hot gas composition, and further wherein thecontinuous curved wall comprises an uppermost area which comprises abyproduct hot gas outlet fluidly connected to the furnace providing anexit from the furnace for the byproduct gases.
 5. The smelting apparatusof claim 4, further comprising a fuel inlet within the continuous curvedwall in fluid communication with the top layer for supplying a fuel tothe furnace and a hot gas inlet within the continuous curved wall influid communication with the top layer for supplying a hot gas to thefurnace for gasifying the fuel, thereby producing the gasified fuel. 6.The smelting apparatus of claim 4, further comprising a hot gasgenerator for providing gasified fuel and a gasified fuel inlet withinthe continuous curved wall in fluid communication with the top layer forsupplying gasified fuel to the furnace.
 7. The smelting apparatus ofclaim 1, wherein the furnace comprises an interior surface, the interiorsurface being lined with a refractory material.
 8. The smeltingapparatus of claim 1, further comprising a cooling system operativelyconnected to the furnace for cooling an exterior surface of the furnace.9. A process for smelting metallic ore, comprising: providing magnetiteand/or iron oxide produced from the metallic ore by hydrometallurgy;producing a hot reducing atmosphere by gasification; and contacting themagnetite and/or iron oxide with the hot reducing atmosphere to producea molten metal, wherein contacting is performed in a smelting apparatuscomprising a cylindrical furnace having a continuous curved wall with alonger axis along a horizontal direction, and end walls joining thecontinuous curved wall and thereby defining a longitudinal volume in thehorizontal direction.
 10. The process of claim 9, wherein the magnetiteis produced by magnetic separation, density, or flotation duringhydrometallurgy.
 11. The process of claim 9, wherein Fe₂O₃ is producedby solvent extraction and acid regeneration during hydrometallurgy. 12.The process of claim 9, wherein the magnetite, the iron oxide and/or thehot reducing atmosphere comprises a source of carbon other than coke orcoal.
 13. The process of claim 9, wherein the hot reducing atmosphere isproduced by gasification of carbonaceous material.
 14. The process ofclaim 9, wherein the contacting of the iron oxide with the hot reducingatmosphere further produces a byproduct gas used as a source of energyfor the hydrometallurgy or for devolatization of biomass.
 15. Theprocess of claim 13, wherein the source of energy is used for acidregeneration for the hydrometallurgy.
 16. The process of claim 9,wherein the molten metal is pig iron.
 17. The process of claim 9,wherein the molten metal is a ferro-manganese alloy, a ferro-nickelalloy, and/or a ferro-vanadium alloy.
 18. The process of claim 9 forsmelting metallic ore containing trace elements, wherein the contactingof the magnetite and/or iron oxide with the hot reducing atmospherefurther produces a slag containing the trace elements.